URBAN DRAINAGE DESIGN MANUAL - Federal Highway Administration

478 Pages·2013·6.48 MB·English

Publication No. FHWA-NHI-10-009
September 2009
(Revised August 2013)

Hydraulic Engineering Circular No. 22, Third Edition

URBAN DRAINAGE
DESIGN MANUAL

1. Report No. 2. Governmental Accession No. 3. Recipient's Catalog No.
FHWA-NHI-10-009
HEC-22
4. Title and Subtitle 5. Report Date

Urban Drainage Design Manual September 2009
Hydraulic Engineering Circular 22, Third Edition (minor revisions August 2013)
6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

S.A. Brown, J.D. Schall, J.L. Morris, C.L. Doherty,
S.M. Stein, J.C. Warner

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

Ayres Associates Inc
3665 JFK Parkway

Building 2, Suite 200

Fort Collins, Colorado 80525
11. Contract or Grant No.

DTFH61-93-C-00096
12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered

Federal Highway Administration National Highway Institute
1200 New Jersey Ave., S.E. 4600 N. Fairfax Dr., Suite 800
Washington, D.C. 20590 Arlington, Virginia 22203 14. Sponsoring Agency Code

15. Supplementary Notes
Project Manager: Dan Ghere, FHWA
Technical Assistants: Joe Krolak, Kornel Kerenyi, FHWA;
Roger Kilgore, Kilgore Consulting and Management
16. Abstract

This circular provides a comprehensive and practical guide for the design of storm drainage systems associated
with transportation facilities. Design guidance is provided for the design of storm drainage systems which collect,
convey, and discharge stormwater flowing within and along the highway right-of-way.
Methods and procedures are given for the hydraulic design of storm drainage systems. Design methods are
presented for evaluating rainfall and runoff magnitude, pavement drainage, gutter flow, inlet design, median and
roadside ditch flow, structure design, and storm drain piping. Procedures for the design of detention facilities are
also presented, along with an overview of storm water pumping stations and urban water quality practices.
This edition presents a major change in the methodology discussed in Chapter 5 for designing channels and in
Chapter 7 for calculating energy losses in storm drain access holes.

17. Key Words 18. Distribution Statement

Storm Drain, Inlets, Storm Water This document is available to the public from the
Management, Water Quality, Best Management National Technical Information Service,
Practices, Pumps, Drainage Design Springfield, Virginia 22151
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 478
Form DOT F 1700.7 (8-72)Reproduction of completed page authorized
HEC-22 – Urban Drainage Design Manual
Listing of Updates/Errata/Corrections
DATE PAGE ACTION BY
8/22/2013 3-32 & Corrected Equations 3-22, 3-24, and Example 3-7 to account for “mm” instead of “cm” dg/jk
3-33 in peak flow equation (now consistent with HDS-2 Equation 6.18).
‘’ 4-1 Clarified that the primary imperative in selecting design spread and design frequency is ‘’
to ensure safety of the travelling public. Clarified other considerations to reflect this.
‘’ 4-50 SI and CU examples: corrected value of E from 0.60 to 0.70 ‘’
o
‘’ 4-82 Added text to note that bridge deck inlet design especially critical as they lack clear ‘’
zones.
‘’ 5-7 to Corrected numbering of equations starting with Equation 5-6 (incorrect labeled as 5-11) ‘’
5-17 and continuing until end of chapter (including renumbering Equation 5-2 to Equation 5-
12 [on page 5-14] to avoid duplication). Checked to ensure proper reference of
equations, text, and examples in Chapter 5.
‘’ 7-57 SI Example, Structure 42, Step 7, Case A: corrected check to remove “d ” ‘’
c
‘’ 7-64 Structure 40, page 7-64, Step 7: ‘’
• Added “new” CaseA: BOC > HGL ; 108.11 m > 108.46 m
o a
• Re-labeled current Case A as Case B
• Re-labeled current Case B as Case D
• Re-labeled current Case D as Case F
‘’ 7-81 & Corrected CU example as described above in Structures 42 and 40 ‘’
7-87
‘’ 10-5 Corrected figure 10-2 to depict a wet pond (not polluntant reduction graph) ‘’
‘’ B-4, B-5 Step 2: Corrected roughness from “0.16” to “0.016” forSI and CU examples ‘’
‘’ various Checked and updated references to latest printed editions of FHWA HECs and HDSs; ‘’
AASHTO Highway Drainage Guidelines and Model Drainage Manual
ACKNOWLEDGEMENTS

First Edition

FHWA published the first edition of this Hydraulic Engineering Circular in November 1996
(FHWA-SA-96-078). The authors were S.A. Brown, S.M. Stein, and J.C. Warner with TVGA
Engineering and Surveying, P.C., Lanse, Pennsylvania. The FHWA Contracting Officers
Technical Representative (COTR) was Chris Dunn, and the Technical Assistants were Phil
Thompson, Johnny Morris, Arlo Waddoups, and Thomas Krylowski.

Second Edition

FHWA published the second edition in July 2001 (FHWA-NHI-01-021). This edition corrected
minor errors and updated the format used for dual units. There were no major changes in
technical content and the original authorship was retained. The editor of this edition was
Johnny Morris with Ayres Associates, Inc, Fort Collins, Colorado. The FHWA COTR was Phil
Thompson and the Technical Assistant was Arlo Waddoups.

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TABLE OF CONTENTS

Section Page

ACKNOWLEDGEMENTS ...................................................................................................... i
CONVERSION FACTORS .................................................................................................... iii
TABLE OF CONTENTS ........................................................................................................ v
LIST OF FIGURES ............................................................................................................. xiii
LIST OF TABLES .............................................................................................................. xvii
LIST OF CHARTS .............................................................................................................. xix
LIST OF SYMBOLS ............................................................................................................ xxi
GLOSSARY ..................................................................................................................... xxvii

CHAPTER 1 INTRODUCTION .......................................................................................... 1-1

CHAPTER 2 SYSTEM PLANNING .................................................................................... 2-1

2.1. Design Objectives ............................................................................................... 2-1
2.2. Design Approach ................................................................................................ 2-1
2.3. Data Requirements ............................................................................................. 2-3
2.4. Agency Coordination ........................................................................................... 2-4
2.5. Regulatory Considerations .................................................................................. 2-5

2.5.1. Federal Regulations ............................................................................................ 2-5
2.5.2. State Regulations ................................................................................................ 2-7
2.5.3. Local Laws .......................................................................................................... 2-8

2.6. Preliminary Concept Development ...................................................................... 2-9

2.6.1. Base Map ............................................................................................................ 2-9
2.6.2. Major vs. Minor Systems ..................................................................................... 2-9
2.6.3. Concept Plan ...................................................................................................... 2-9
2.6.4. System Components ......................................................................................... 2-10

2.6.4.1 Stormwater Collection ....................................................................................... 2-10
2.6.4.2 Stormwater Conveyance ................................................................................... 2-11
2.6.4.3 Stormwater Discharge Controls ........................................................................ 2-11
2.6.4.4 Flood Water Relief ............................................................................................ 2-12

2.6.5. Special Considerations ..................................................................................... 2-12

CHAPTER 3 URBAN HYDROLOGIC PROCEDURES ...................................................... 3-1

3.1. Rainfall (Precipitation) ......................................................................................... 3-1

3.1.1. Constant Rainfall Intensity .................................................................................. 3-1
3.1.2. Dynamic Rainfall (Hyetograph) ........................................................................... 3-1
3.1.3. Synthetic Rainfall Events .................................................................................... 3-3

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3.2. Determination of Peak Flow Rates ...................................................................... 3-4

3.2.1. Stochastic Methods ............................................................................................. 3-4
3.2.2. Rational Method .................................................................................................. 3-5

3.2.2.1. Runoff Coefficient ............................................................................................... 3-5
3.2.2.2. Rainfall Intensity ................................................................................................. 3-8
3.2.2.3. Time of Concentration ......................................................................................... 3-8

3.2.3. USGS Regression Equations ............................................................................ 3-16

3.2.3.1. Rural Equations ............................................................................................... 3-16
3.2.3.2. Urban Equations ............................................................................................... 3-16

3.2.4. SCS (NRCS) Peak Flow Method ....................................................................... 3-18

3.3. Development of Design Hydrographs ................................................................ 3-25

3.3.1. Unit Hydrograph Methods ................................................................................. 3-25

3.3.1.1. Snyder Synthetic Unit Hydrograph .................................................................... 3-25
3.3.1.2. SCS (NRCS) Tabular Hydrograph ..................................................................... 3-26
3.3.1.3. SCS (NRCS) Synthetic Unit Hydrograph ........................................................... 3-32

3.3.2. USGS Nationwide Urban Hydrograph ............................................................... 3-35

CHAPTER 4 PAVEMENT DRAINAGE ............................................................................... 4-1

4.1. Design Frequency and Spread ............................................................................ 4-1

4.1.1. Selection of Design Frequency and Design Spread ............................................ 4-1
4.1.2. Selection of Check Storm and Spread ................................................................ 4-3

4.2. Surface Drainage ................................................................................................ 4-3

4.2.1. Hydroplaning ....................................................................................................... 4-4
4.2.2. Longitudinal Slope .............................................................................................. 4-4
4.2.3. Cross (Transverse) Slope ................................................................................... 4-5
4.2.4. Curb and Gutter .................................................................................................. 4-6
4.2.5. Roadside and Median Channels ......................................................................... 4-7
4.2.6. Bridge Decks ...................................................................................................... 4-7
4.2.7. Median Barriers ................................................................................................... 4-8
4.2.8. Impact Attenuators .............................................................................................. 4-8

4.3. Flow in Gutters .................................................................................................... 4-8

4.3.1. Capacity Relationship ......................................................................................... 4-8
4.3.2. Conventional Curb and Gutter Sections ............................................................ 4-10

4.3.2.1. Conventional Gutters of Uniform Cross Slope ................................................... 4-10
4.3.2.2. Composite Gutter Sections ............................................................................... 4-11
4.3.2.3. Conventional Gutters with Curved Sections ...................................................... 4-15
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